This research aims at developing a methodology based upon confirmation parameters which will provide criteria for assessing pre-hospital EMT diagnostic and therapeutic decisions. Cohorts of patients with peripheral fractures, cardiac arrest, abdominal traumas, and suspected myocardial infarctions will be the test group which will be the core of this study. Measurements obtained in the Emergency Room will be the basis for the following confirmation parameters: 1. For peripheral fractures, false positive and false negative rates of splinting errors will be incorporated into Receiver Operating Characteristic (ROC) curves which will reflect the EMT's recognition and appropriate treatment of fractures. 2. For cardiac arrest, arterial blood pH will be a confirmation measurement of the effectiveness of cardiopulmonary resuscitation (CPR). The distribution of pH values will be plotted as a function of the time interval between the time of cardiac arrest and the time of the arrival of the EMT. 3. For cohorts of patients with solid organ, vascular or visceral abdominal trauma, distribution of the rates of change per unit time for blood pressure, pulse rate Double Product will be correlated with the number of units replaced in the first hour after arrival in the emergency room. These rates of change will be used to assess the EMT's decision about the relative severity of the patient's condition and the subsequent need for fluid replacement. 4. For patients with suspected myocardial infarctions in the opinion of the emergency room physicians, the relative contribution of the ten Imminent MI (IMIR) symptoms to the false positive and false negative rates of recognition by the EMTs will be assessed. These measurements based on a group of 59 graduates of the national 81-hour EMT course can be used as standards against which the performance of other groups of EMTs in different types of training programs or at other levels of training can be compared.